Details

Autor(en) / Beteiligte

• Voitenko, Yuriy
• De Keyser, Johan

Titel

MHD-KINETIC TRANSITION IN IMBALANCED ALFVÉNIC TURBULENCE

Ist Teil von

• Astrophysical journal. Letters, 2016-12, Vol.832 (2), p.L20-L20

Ort / Verlag

United States: The American Astronomical Society

Erscheinungsjahr

2016

Quelle

EZB Free E-Journals

Beschreibungen/Notizen

• ABSTRACT Alfvénic turbulence in space is usually imbalanced: amplitudes of waves propagating parallel and anti-parallel to the mean magnetic field are unequal. It is commonly accepted that the turbulence is driven by (counter-)collisions between these counter-propagating wave fractions. Contrary to this, we found a new ion-scale dynamical range of the turbulence established by (co-)collisions among waves co-propagating in the same direction along . Co-collisions become stronger than counter-collisions and produce steep non-universal spectra above certain wavenumbers dependent on the imbalance. Spectral indexes of the strong turbulence vary around , such that steeper spectra follow larger imbalances. Intermittency steepens the −3 spectra further, up to −3.7. Our theoretical predictions are compatible with steep variable spectra observed in the solar wind at ion kinetic scales, but further verifications are needed by correlating observed spectra with measured imbalances.